Orphan Instances with GHC 6.8

Simon Peyton-Jones simonpj at microsoft.com
Wed Oct 17 12:24:17 EDT 2007


What you say rings no bells.  I don't see how to make progress without more info.
Perhaps show the module that elicits the unexpected orphan message?

Simon

| -----Original Message-----
| From: Adrian Hey [mailto:ahey at iee.org]
| Sent: 17 October 2007 17:04
| To: glasgow-haskell-users at haskell.org; Simon Peyton-Jones
| Subject: Re: Orphan Instances with GHC 6.8
|
| Hello again,
|
| Adrian Hey wrote:
| > Hello Folks,
| >
| > One thing different from 6.6 and 6.8 is I find that with -Wall
| > I get a lot more warnings about orphan instances, even if the
| > code has not changed.
| >
| > Has the definition of what an Orphan instance is changed?
| >
| > Or is this a bug? If so, is the bug in 6.6 or 6.8?
| >
| > I can make them go away with the -fno-warn-orphans flag,
| > but I'm still curious as to why I didn't have to do this before.
|
| Sorry, this situation seems more complex than this. I can't quite
| figure out whats going on, in fact this but it may to be related
| to some other change I've made in the code to get since 6.8.
|
| The strange thing (to me) is that if I take exactly the same module
| and use it in 2 different packages (which are compiled with the same
| ghc options AFAIK), one gives me the orphan warning and one doesn't.
| Does that make sense? (I.E. Is "Orphanness" somehow context dependent?)
|
| Thanks
| --
| Adrian Hey



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